Tow vehicles and trailers are often connected using a hitch arrangement at the rear of the tow vehicle and a trailer coupler at the front of the trailer. The hitch typically has a ball of one of a few standard diameters, and the trailer coupler typically has a correspondingly sized socket to accept the ball. To connect the tow vehicle and trailer, the front of the trailer is first elevated to a height adequate to allow the trailer coupler to clear the top of the ball, and then the tow vehicle is backed up to the trailer.
When the hitch and trailer coupler are sufficiently close, the trailer coupler is lowered onto the hitch ball and secured. But it is difficult to see the two connection points while backing most tow vehicles. Thus the assistance of another person to guide the operator is often needed to prevent backing the tow vehicle into the trailer and damaging one or both, either at the connection points or other surface areas. Without assistance, the operator often attempts to manually move the trailer close enough to the tow vehicle to engage the hitch, risking strain or injury.
Frequently, the operator must turn their back, shoulders, and neck into ergonomically stressful positions to look through the rear window to judge the proximity of the tow vehicle to the coupler. Alternately, the operator can repeatedly exit the tow vehicle, inspect the proximity of hitch ball and trailer coupler, and make repeated attempts to adjust the tow vehicle by moving the tow vehicle forward, backward, and to the left or right, which becomes tedious.
The problem of connecting a trailer to a towing vehicle has spurred development of several attempts at solution. Early efforts to address the problem included trailer-mounted mirrors. These include U.S. Pat. No. 3,295,914 to Dietrich (Jan. 3, 1967), with a trailer-mounted mirror. In U.S. Pat. No. 3,524,701 to Strohmeier (Aug. 18, 1970), a mirror is mounted on the trailer jack post. In U.S. Pat. No. 3,767,292 to Rutkowski (Oct. 23, 1973), and in U.S. Pat. No. 4,163,606 to Granno (Aug. 7, 1979), mirrors are mounted on gas bottles secured to the trailer. In U.S. Pat. No. 3,858,966 to Lowell, a mirror is mounted on the trailer. U.S. Pat. No. 5,235,468, to Stephens (Aug. 10, 1993) employs a trailer mount. U.S. Pat. No. 5,309,289 to Johnson (May 3, 1994) uses a mirror mounted on the towed trailer. U.S. Pat. No. 6,076,847 to Thornton (Jun. 20, 2000) also mounts a mirror on a trailer. U.S. Pat. No. 6,239,926 to De Shazer (May 29, 2001) attaches permanently to a single trailer. Design patents granted on trailer-mounted mirrors include U.S. Pat. No. D329,631 to Cameron (Sep. 22, 1992); U.S. Pat. No. D340,219 to Moon (Oct. 12, 1992); and U.S. Pat. No. D344,485 to Linne et al. (Feb. 22, 1994).
However, trailer-mounted mirrors have a number of disadvantages. Because the mirror is mounted on the trailer, the angle from which the tow vehicle can approach the trailer is severely constrained to a narrow range directly in front of the trailer. Each trailer requires a separate device, and most are not easily transferable to another trailer in case more than one trailer must be moved by the same tow vehicle. Because some trailer mounted mirrors are positioned vertically with respect to the trailer coupler and hitch, they are unsuitable for determining from a horizontal perspective the trailer coupler height.
Other efforts to address the problem include mirrors attached to the tow vehicle. While these solve some of the problems inherent in trailer-mounted mirrors by providing temporary attachment of a backing-aid mirror to the tow vehicle, several new problems may arise. For example, magnets have been employed as mounting aids in U.S. Pat. No. 4,905,376 to Neeley (Mar. 6, 1990); and U.S. Pat. No. 5,482,310 A to Staggs (Jan. 9, 1996). However, magnets must be strong enough to be stable but weak enough to disengage easily, they can scratch paint during attachment, adjustment, and detachment, and are unsuitable for use on non-metallic vehicles.
Other problems occur when magnets used for reversible attachment of a backing-aid mirror to a tow vehicle are adhered by suction cups, such as those described in: U.S. Pat. No. 4,925,287 To Lord et al. (May 15, 1990); U.S. Pat. No. 4,936,669 to Wun (Jun. 26, 1990); U.S. Pat. No. 5,111,342 to Quesada (May 5, 1992); U.S. Pat. No. 5,313,337 to Byers (May 17, 1994); U.S. Pat. No. 5,550,681 to Mazarac (Aug. 27, 1996); U.S. Pat. No. 5,784,213 to Howard (Jul. 21, 1998); and U.S. Pat. No. 5,971,555 to Wilcox, et al. (Oct. 26, 1999). Although suction cups can be attached to windows, avoiding the problem of scratching paint, they are subject to different weaknesses, which are circumvented by the present invention.
For example, the use of suction cups requires that the tow vehicle have a surface that is sufficiently flat, clean, and smooth for correct adhesion, which cannot be guaranteed under actual use conditions. If mounted on a painted surface, the cups can scratch the paint. Sometimes, suctions cups are prone to overly forceful attachment, and thus can be difficult to remove. In cold weather, suction cups can lose their flexibility and become unsuitable for their intended use. In rain or when water spray is blown onto the intended mounting surface, suction cups may allow slippage.
Vehicles having a tailgate, such as pickup trucks, some station wagons, and some sports utility vehicles, allow mounting to the edge of the tailgate. Backing aid mounts for tailgates include U.S. Pat. No. 4,905,376 to Neeley (Mar. 6, 1990); U.S. Pat. No. 4,951,913 to Queseda (Aug. 28, 1990); U.S. Pat. No. 5,180,182 to Haworth (Jan. 19, 1993); U.S. Pat. No. 5,550,681 to Mazarac (Aug. 27, 1996); U.S. Pat. No. 5,657,175 to Brewington (Aug. 12, 1997); U.S. Pat. No. 5,784,213 to Howard (Jul. 21, 1998); and U.S. Pat. No. 5,971,555 to Wilcox, et al. (Oct. 26, 1999). However, these devices are limited in scope of application to vehicles having a tailgate. In addition, most are mounted on the centerline of the tow vehicle, so that in use they do not provide any information about the relative height of the tow vehicle hitch ball and trailer coupler as the tow vehicle approaches the trailer, and are only effective when the tow vehicle and trailer are oriented in a narrow range of angles relative to each other.
Others have provided attempts at solutions to trailer alignment issues by requiring permanent modifications to the tow vehicle or tow vehicle hitch. For example, U.S. Pat. No. 4,469,405 to Chin-Wun (Sep. 4, 1984), comprises two mirrors, one mounted at the front and one at the rear, to generally enable the operator to see the rear of a vehicle by looking up into the mirror mounted at the front of the vehicle. U.S. Pat. No. 5,625,500 to Ackerman (Apr. 29, 1997) mounts to the center of a rear window. U.S. Pat. No. 5,825,564 to Mazarac (Oct. 20, 1998) requires a special support frame; and U.S. Pat. No. 6,213,608 to Osgood (Apr. 10, 2001) requires special modifications to the hitch or vehicle. However, these attempts at solution require permanent modifications of the tow vehicle and as a result are only suitable for vehicles having the special modification.